The majority of work in smoking has focused on the select group of individuals who are ready to quit smoking and/or have actively sought formal cessation treament. However, recent data suggests that the majority of smokers are not ready to take action to quit, and those who are considering quitting are not interested in formal cessation programs. Traditional approaches to treatment may neglect the majority of the at-risk population of smokers. The hospital setting has been used in several cessation studies targeting individuals who have developed smoking-related illnesses. However, few hospital-based studies have focused on smokers who have not yet experienced serious health consequences of smoking. Use of hospitalization as an impetus for smoking cessation among individuals at high-risk for developing chronic disease offers an important opportunity for primary prevention. The present study will target the large underserved population of hospitalized smokers who do not yet have documented smoking-related illnesses. Several theories of behavior change and initial pilot work suggest that personalized, health-related feedback that increases smokers' perception of their vulnerability to smoking-related illnesses, may significantly impact on the processes postulated to mediate behavior change. This study will evaluate the efficacy of a personalized health feedback (PHF) intervention in motivating smokers to attempt and maintain smoking cessation. The PHF intervention will be compared to a self-help intervention. The impact of PHF on the mechanisms proposed to mediate behavior change will be evaluated. The present study is a relatively low-cost effort to determine the efficacy of this approach to smoking cessation, that may have a major public health impact. If found to be effective, the PHF intervention could be adapted to a variety of settings (e.g. outpatient medical practices, worksites), and could easily be adpated for use with low literacy and underserved populations.